What’s that you’re doing, Mr. Arnold?

“Is everything here really precise to the last micrometer? Aircraft components call for maximum accuracy. Sometimes even a few thousandths of a millimeter, or micrometers, can make all the difference. High-precision parts – such as these bearing shells, which should soon be in service inside the auxiliary power unit (APU) of an Airbus A320 – need to be very carefully measured before they can be installed in an aircraft. With the aid of a coordinate measuring machine, I check whether the bearing shells meet the prescribed specifications. The joystick lets me move a measuring probe freely to obtain a thorough scan of each shell. Alternatively, I can program the machine so that it works fully automatically. Should I determine deviations from the target values, a precisely regulated process will be set in motion. The component then goes back to the technician responsible, who will either rework it – or scrap it.”